On 9th April, 1682, René-Robert Cavelier, Sieur de La Salle, claimed the Mississippi basin in the name of the France by erecting a cross and a column, and by burying a inscribed copper plate. He had canoed down the Mississippi River with eighteen Native Americans from Fort Crevecoeur, which was located near what is now Peoria, Illinois. He named the region, la Lousiane (Louisiana), in honour of King Louis XIV.

Cavelier, a destitute ex-Jesuit, had travelled in search of a new life in the Americas in 1667. He became an explorer based in New France, now part of Canada, and journeyed extensively throughout North America under the patronage of the Governor General of New France, Louis de Buade de Frontenac, who secured a title and a fur concession for him. He was murdered whilst on an expedition in Texas on 19th March, 1687, by mutinous members of his party.

You can read more about Cavelier in his biography on the Dictionary of Canadian Biography Online site.